Combine lemon juice with agave and EVOO. Add cabbage, parsley and onions, and season liberally with salt and pepper. Toss to coat.

Cut fish into large chunks or leave as filets and coat with EVOO. Season liberally with seafood seasoning and grill to flaky and opaque. For filets, grill on a wooden plank soaked in water -- sturdy fish like halibut can go directly on the grill.

Serve fish on a platter broken into irregular pieces with lemon and lime wedges alongside. Assemble tacos by combining some fish, slaw and Grilled Romesco Sauce in a tortilla.